Earnings Per Share, Share Repurchases and Dividends on Common Stock #2 (Unaudited) (Details) - $ / shares shares in Millions	1 Months Ended			3 Months Ended		6 Months Ended
	May. 31, 2015	May. 31, 2014	May. 31, 2013	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share, Basic and Diluted [Abstract]
Dilutive effect of of stock awards and options granted to employees under stock-based compensation plans				1.9	2.8	2.3	3.4
Anti-dilutive stock options excluded from computation of earnings per share				0.0	0.0	0.0	0.0
Common stock dividends per share, declared (in dollars per share)	$ 0.80	$ 0.70	$ 0.61			$ 1.5	$ 1.31
Increase in quarterly common stock dividend (percent)	14.00%	15.00%